Summary: Researchers at the University of California, San Francisco (UCSF) report that a freeze-dried, platelet-derived product called Thrombosomes shows strong potential to treat traumatic brain injury (TBI). Built originally to control battlefield hemorrhage, this shelf-stable biologic appears to stabilize injured cerebral blood vessels, reduce bleeding at the injury site and lessen the delayed, dangerous brain swelling (cerebral edema) that often follows TBI. The findings, derived from mouse experiments and laboratory models, point to a treatment that could be carried on ambulances and used in remote emergency settings where fresh platelets are not available.
Thrombosomes are produced by freeze-drying platelets with trehalose, a sugar that preserves key platelet factors. Unlike donor-derived fresh platelets, which require refrigeration and expire within a week, Thrombosomes can be stored at room temperature for up to five years, offering a practical, durable option for early intervention in acute brain trauma.
Key Facts
- Long Shelf Life: Freeze-dried platelets preserved with trehalose retain activity for up to five years at room temperature, versus a seven-day refrigerated shelf life for fresh platelets.
- Vascular Stabilization: Thrombosomes contain high levels of proteins that activate receptors on endothelial (blood vessel) cells, reinforcing vessel integrity and reducing leakiness that leads to cerebral edema.
- Beyond Clotting: While fresh platelets provide clotting support, Thrombosomes appear to concentrate additional bioactive factors that reduce inflammation and protect the blood-brain barrier after injury.
- Clinical Development: The product is already in Phase II trials for bleeding disorders, so its safety profile in humans is established and clinical testing for TBI could proceed more rapidly.
Source: UCSF
A shelf-stable blood product for ambulances and remote clinics shows promise for treating traumatic brain injuries.
Traumatic brain injury causes immediate bleeding and, over hours to days, a cascade of vascular leak and inflammation that produces cerebral edema. Because the skull is a rigid container, swelling quickly raises intracranial pressure and can interrupt blood flow, causing further brain injury or death. Current medical options to control swelling are limited largely to surgical measures such as decompressive craniectomy; there are no widely effective drugs that directly prevent the vascular leak that causes edema.
In laboratory experiments on endothelial cell layers and three-dimensional vessel organoids, Thrombosomes made vessel walls more resilient to damage. In a mouse model of TBI, animals treated with Thrombosomes either one hour or 24 hours after injury demonstrated reduced intracranial hemorrhage, improved vascular integrity, and lower markers of neuroinflammation compared with controls.
The researchers found that Thrombosomes are enriched in Angiopoietin-1 (Ang-1), a protein that signals through the Tie2 receptor pathway, a central regulator of endothelial stability. Blocking Tie2 increased blood-brain barrier permeability after injury, while administration of the dried platelet product counteracted that effect, implicating Ang-1 as a key mediator of the observed protection. The team describes Ang-1 as one prominent factor among a possible cocktail of beneficial molecules concentrated by the freeze-drying process.
“Platelets carry many potent factors that go beyond clotting,” said Shibani Pati, MD, PhD, director of the UCSF Center for Research in Transfusion Medicine and Cell Therapies and senior author of the study. “In our mouse model of TBI, Thrombosomes appeared to concentrate these factors, making them more effective than fresh platelets at reinforcing damaged vessels and reducing inflammation.”
Because Thrombosomes are already undergoing Phase II clinical trials for bleeding disorders, their safety in humans has begun to be established. That existing clinical pathway could speed the process of evaluating the product for TBI, where rapid, pre-hospital treatment has the potential to change outcomes for patients who would otherwise not reach a trauma center in time.
Authors: Alpa Trivedi, PhD; Byron Miyazawa; Haoqian Zhang, PhD; Longhui Qiu, PhD; Daniel Potter; Austin Edwards; Lindsay Vivona; Maximillian Lin; Callie Keane; Huimin Geng, PhD; Simon J. Cleary, PhD; Alison Nair, MD; Mark R. Looney, MD; Shibani Pati, MD, PhD. (See the published paper for the full author list and detailed contributions.)
Funding: Supported in part by the Department of Defense (W81XWH‐19‐1‐0462 BA180248). See the paper for the complete funding statement.
Key Questions Answered:
A: The skull is rigid and leaves no room for swollen brain tissue to expand. When the brain swells, intracranial pressure rises, which can compress blood vessels and reduce cerebral blood flow, causing secondary injury. Surgical removal of part of the skull (craniectomy) can relieve pressure, but a drug that prevents the underlying vascular leak would change how clinicians manage TBI.
A: Freeze-drying with trehalose preserves and concentrates bioactive molecules that fresh platelets lose over time. Thrombosomes remain stable at room temperature for years, enabling immediate treatment in pre-hospital settings instead of waiting for refrigerated blood products at a trauma center.
A: The core mechanism—stabilizing leaky blood vessels and protecting the blood-brain barrier—is relevant to hemorrhagic stroke and other forms of acute vascular injury in the brain. Further studies will be needed to test safety and efficacy in those conditions.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full by the editorial team.
- Additional context was added by staff to clarify implications for clinical care and research.
About this TBI and neurology research news
Author: Levi Gadye
Source: UCSF
Contact: Levi Gadye – UCSF
Image: Credit to Neuroscience News
Original Research: A Dried Platelet-Derived Biologic for Blood-Brain Barrier Repair and Hemorrhage Control Following TBI in Mice. Authors include Alpa Trivedi, Byron Y. Miyazawa, Haoqian Zhang, Longhui Qiu, Daniel Potter, Austin William Edwards, Lindsay Vivona, Maximillian Lin, Callie Keane, Huimin Geng, Simon J. Cleary, Alison Nair, Michael M. Fitzpatrick, Mark R. Looney, and Shibani Pati. DOI: 10.1182/blood.2025031826. (Published in Blood; access closed.)
Abstract
A Dried Platelet-Derived Biologic for Blood-Brain Barrier Repair and Hemorrhage Control Following TBI in Mice
Traumatic brain injury (TBI) is a leading cause of death in people aged 18–44 and causes acute complications such as intracranial hemorrhage (ICH) and cerebral edema. The blood-brain barrier (BBB) and vascular stability are emerging therapeutic targets for limiting these life-threatening effects. This study evaluates a first-in-class freeze-dried platelet-derived biologic (FDPlts, also called Thrombosomes) in a murine TBI model.
Transfusion of FDPlts significantly reduced post-TBI intracranial hemorrhage, restored cerebral perfusion, and decreased blood-brain barrier permeability. Treated animals showed reduced intravascular leukocyte accumulation and lower neuroinflammation, with decreased microglial activation, astrocyte reactivity, and macrophage infiltration. Transcriptomic analysis of cortex and hippocampus indicated downregulation of gene networks associated with inflammation and fibrosis, suggesting a reparative influence on post-injury tissue remodeling.
Mechanistically, FDPlts are enriched in Angiopoietin-1, which signals via the Tie2 receptor to promote endothelial stability. Inhibition of Tie2 worsened BBB permeability after TBI, an effect that FDPlt administration attenuated, implicating Ang-1 as a principal mediator of the vascular-protective effects. These results demonstrate that a dried, platelet-derived biologic can promote vascular repair and neuroprotection after TBI in mice, supporting further preclinical and clinical investigation.